'end' event not called on connected socket wrapped with tls

[zivbr]

• Version: v6.9.4, v7.4.0
• Platform: Linux pc 4.2.0-30-generic docs: re-word project messaging #36-Ubuntu SMP Fri Feb 26 00:58:07 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
• Subsystem: net, tls

When wrapping an existing socket with tls, the socket's 'end' event is not called if the socket was already connected.

Example:

In this case 'end' will be called:

var Socket = require('net').Socket;
var tls = require('tls');

var HOST = 'www.google.com';

var socket = new Socket();
var tlsOptions = {
  host: HOST,
  socket: socket
};

socket.on('close', function() { console.log('close'); });
socket.on('end', function() { console.log('end'); });

var tlsSocket = tls.connect(tlsOptions, function() {
  console.log('connected');
  tlsSocket.end();
});

socket.connect({
  port: 443,
  host: HOST
});

In this case 'end' will not be called:

var Socket = require('net').Socket;
var tls = require('tls');

var HOST = 'www.google.com';

var socket = new Socket();
var tlsOptions = {
  host: HOST,
  socket: socket
};

socket.on('close', function() { console.log('close'); });
socket.on('end', function() { console.log('end'); });

socket.connect({
  port: 443,
  host: HOST
});

var tlsSocket = tls.connect(tlsOptions, function() {
  console.log('connected');
  tlsSocket.end();
});

[webertrlz]

*I'm not sure if this is related because the end event is emitted when the other end sends a fin
package, but I'd like to understand why this happens if there is a discussion on this topic.

in this piece of code, the 'end' event is also not emitted if we hit CTRL^C on the Client side:

const server = require('net').createServer((socket)=>{
	var interval =	setInterval(()=>{ socket.write("hello socket"); }, 10);
	socket.on('end', ()=>{ console.log('end'); });
	socket.on('close', ()=>{ console.log('close'); clearInterval(interval); });
	socket.on('error', (error)=>{ console.log(error);	});
}).listen(9999);

then on a shell do: telnet 0 9999
wait a few and then hit CTRL^C then close telnet (with CTRL^]q)

if we don't hit CTRL^C and just close the telnet client, the end event is emitted.

[Trott]

@nodejs/crypto @nodejs/http

[ajimix]

I'm having the same problem with node 8.9.4

[oyyd]

According to the code here:

node/lib/_tls_wrap.js

Lines 312 to 315 in 097896b

	if ((socket instanceof net.Socket && socket._handle) || !socket)
	wrap = socket;
	else
	wrap = new StreamWrap(socket);

A net.Socket instance that doesn't call connect will be wrapped in a StreamWrap as the socket._handle here will be null.

The problem is that a socket not wrapped in StreamWrap won't emit data, drawn, end events because its TCP handle will be "occupied" by a TLSWrap. However, events like lookup, connect, ready, close still works. Whether the net.Socket is wrapped in StreamWrap or not will make it behave differently.

[oyyd]

Considering how TLSWrap and StreamBase work, I guess it's not ideal to "fix" this issue as it may result in reduced performance.
Edit: Find that http2 also use StreamWrap so that I guess it's okay.

Personally, for anyone has the same problem, directly use tlsSocket if possible. Otherwise, wrap your net.Socket with stream.Duplex.

[jasnell]

@ronag ... this may be one that interests you. It could be this is already fixed but not likely, but it falls in line with making all the streams things work consistently.

[ronag]

I will take a look.

[ronag]

It's still a problem. Or at least it still seems to behave in the same way as when OP created issue.

[ronag]

I'm actually more surprised that end is emitted in one of the cases.

[ronag]

@jasnell: I find that 'end' makes very little sense for sockets at the moment, since we don't really have a graceful vs non-graceful connection disconnect. So whether an when 'end' is emitted is (for me) somewhat pseudo random at the moment in general, i.e. we don't have well defined semantics for this. Or at least not that I'm familiar with.

Would be interesting to understand why there is a difference between OP's examples and why they differ. However, not sure what to do what that information.

At the moment I would recommend not using 'end' at all when working with sockets and only use 'close'.

Refs: #31916

[ronag]

At the moment I would recommend not using 'end' at all when working with sockets and only use 'close'.

@jasnell @addaleax Thoughts on the above? Should we document it?